Japanese Patent Application Publication No. 1995-47171 (JP1995-47171A: Patent Document 1) discloses a play toy (traveling toy system) used in a horse racing game, which includes a lower track member, an upper track member disposed above the lower track member with an interval therebetween and having a bottom surface facing the lower track member and a top surface facing the bottom surface in the thickness direction thereof, a carrier (self-driven towing vehicle) provided with a driving source and running by itself on the lower track member, and a moving object (towed object) connected to the carrier (self-driven towing vehicle) by means of magnetic attraction force and running on the top surface of the upper track member. In this conventional play toy, a toy horse fabricated as a dedicated accessory is mounted on the moving object (towed object).
U.S. Pat. No. 6,012,957 (Patent Document 2) discloses a traveling toy system in which a four-wheel toy vehicle running on an upper track member and a self-driven towing vehicle running on a lower track member are connected by means of magnetic force.
U.S. Pat. No. 6,095,892 (Patent Document 3) discloses a traveling toy system in which a two-wheel toy vehicle running on an upper track member and a self-driven towing vehicle running on a lower track member are connected by means of a mechanical connecting means.    Patent Document 1: Japanese Patent Application Publication No. 1995-47171 (JP1995-47171A)    Patent Document 2: U.S. Pat. No. 6,012,957    Patent Document 3: U.S. Pat. No. 6,095,892